1. Field of the Invention
The present invention relates to an optical engine of a projection display device, more particularly, to a polarizer module in an optical engine.
2. Description of the Prior Art
As the science and technology develop rapidly, projection display devices are applied in different areas such as the projection display in a big meeting, commercial projection screen or television, and works with the contents of brief report for an instant diagrammatic screen display. To provide a high brightness and clear image of the projection on screen, the projection display device generally uses a high-power light bulb as the projecting light source. However, using a high-power light bulb will cause the problem of generating high temperature. Therefore, the way of quickly assembling the projection display device and effectively dispersing heat to avoid deterioration to the function of the optical components due to the high temperature and enhancing the product quality and competitiveness become the subjects of research and development in the industry.
FIG. 1 shows an imaging assembly 10 of a prior-art projection display device. A projecting lamp (not shown in the figure) is installed under the imaging assembly 10 for producing a white light beam. The white light beam is separated into three colored light which are red, green and blue by the X-plate 12 in the external casing 11 of the imaging assembly 10. Each separated colored light is guided into three polarizer modules 13 that are comprised of a polarizer and a half-wave plate, and three modulation units that are composed of three light valves 14 for modulation. Then, each modulated light is passing through a X-cube 15 for light combination, and is projected onto a screen by a projection lens (not shown in the figure) at the front end of the X-cube 15. In addition, two fans 16 are disposed in the intervals of the three light valves 14 on the side of the external casing 11 for dispersing heat.
As shown in FIGS. 2 and 3, the prior-art polarizer module 13 has an aslant surface 1311 on a L-shape base 131, and a polarizer 132 adhered onto a concave surface 1313 at the top of the aslant surface 1311, and two fixing bolts 133 passing two slots 134 to fix a fixed base 135, a half-wave plate 136 disposed at a concavesurface 1351 on the top of a fixed base 135 corresponsive to the concave surface 1313, and a block 137 protruded from the center of the lower side of the fixed base 135 and embedded into a recess 1312 at the center of the lower end of the aslant surface 1311. By means of the rotation of adjusting bolts 138 on both sides at the bottom end of the aslant surface 1311, the block 137 is pushed sideway to drive the half-wave plate 136 on the fixed base 135 to make a planar angle adjustment for searching for the optimal polarization effect. Finally, the fixing bolt 133 secures the fixed base 135 into position. However, the distance between the half-wave plate 136 and the polarizer 132 of the prior-art polarizer module 13 is too close, the heat dispersion effect is poor, and thus will shorten the life of the polarizer module 13. Further, the half-wave plate 136 needs to simultaneously adjust the adjusting bolts 138 on both sides to complete the positioning, not just wasting time, but also very inconvenient. In addition, the half-wave plate 136 and the polarizer 132 are only supported by the two dimensional concave surfaces 1313, 1351, and it is difficult to accurately align them for gluing. Furthermore, a special sectional bolt is used for the fixing bolt 133 to avoid affection to the positioning of the half-wave plate 136, which also increases the complexity of the components. Therefore, the prior-art polarizer module 13 still has several shortcomings that require improvements.
An object of the present invention is to provide a polarizer module to increase the distance between the half-wave plate and the polarizer for improving the ventilation and heat dispersion effects, and extending the lifetime.
Another object of the present invention is to provide a polarizer module to increase the supporting surface, such that the half-wave plate and the polarizer can be positioned accurately for easy installation by gluing.
Another object of the present invention is to provide a polarizer module to simplify the adjusting operation and save the assembling time by using a single adjusting bolt to adjust the position of the half-wave plate.
Another further object of the present invention is to provide a polarizer module by using simple screws and washers to avoid affections to the adjustment to the positioning of the half-wave plate and simplify the complexity of components.
To achieve the foregoing objectives, the present invention comprises a polarizer adhered on a flange plate at the top end of a L-shape base, an aslant surface on one side of the base, two sleeve screws protruded from the center of the aslant surface, an air duct defined between an upper base and a lower base of a Z-shape fixed base, two slots disposed on the lower base for receiving the sleeve screws, and two fixing bolts securing the washers onto the sleeve screw to limit the fixed base on the aslant surface of the base. A supporting surface is formed at a flange disposed downward at both ends of the upper base of the fixed base for gluing a half-wave plate. An adjusting mechanism protruded from the lower side of the fixed base extends into a recess at the lower end of the aslant surface; a screw hole is disposed on a side of the base and having an adjusting slot with its end propping one side of the adjusting mechanism; and an elastic member with its ends respectively fixed to a side of the base and a hole of the adjusting mechanism. The adjusting mechanism at the lower side of the fixed base adjusts the half-wave plate to an optimal polarized position.